Many thanks to David and others who have commented so far on rigs and mast thickness etc.

I have now re-drawn the Reddish sail plan making the sail about 150 sq ft and also done a drawing of the fantail with about the same area of sail. Album on my page. To keep the mast short, have it in a convenient place for fitting (with or without a tabernacle), keep the centre of effort in the right place and to keep the number of sail panels reasonably low for such a small boat it looks like the Reddish sail would be best. So..

• Would there still be a problem with the sheeting? The current position of the mainsheet block in right above the transom.
• Would it be possible to reduce the number of panels to 5 while keeping the same sail area?
• Where could I look for a 90mm aluminium mast and also look at options for carbon fibre or wood (to go in a tapernacle)?
• Where can I look to learn more about the Reddish plan - any advantages and disadvantages?

I would suggest a tube of 100mm diameter x 3mm wall for the Nimrod, if the AR is going to be high, but perhaps a 90mm diameter x 3mm wall will be enough for a low AR. The heavy drop keel is likely to give the boat quite a lot of ultimate stiffness - more than is the case with the YM Senior's plate centreboard. Unfortunately, the Aluminium Lighting Company do not list a tapered tube as small as this, so it's going to have to be a hybrid mast.

Comparing that with the YM Senior, a tube of 80mm diameter x 3mm wall has already been bought, but note that this is very much a case of fitting the rig to the owner as well as the boat. Martin suffered a severe injury a while ago, and as a consequence this boat will be sailed more gently than the Joe 17 is likely to be. The mast needs to be a light as possible and the tabernacle arranged so that stepping is as easy as possible.

The mast for the YM Senior measures 6.4m above the foredeck. Scaling off the sailboatdata drawing of the Westerly Nimrod, the bermudan mast measures 7m above the foredeck. Are you physically measuring your mast, or measuring off a different drawing, David? Adding the bury, the junk mast would maybe be a little longer than the bermudan mast. But if we were to put a junk mast in a tabernacle, it would be a little shorter than the bermudan mast.

Anyway, if you really prefer a mast that is shorter than that, I agree with Chris that the fantail planform would suit the boat. The Reddish planform has to be sheeted a long way aft if you are to avoid snagging the sheet spans on the battens (because of the convex leech), and I doubt whether you can get far enough aft with your deck blocks. However, drawing it out costs nothing, and it's as well to explore all avenues before buying costly materials.

Many thanks David

That is helpful and very interesting. The thing that strikes me straight away, however, is how incredibly long the mast is (longer than the original) which could be impractical on a trailor sailor, unless made in very light material. 

Going back to your observation that the Reddish rig doesn't look right on my boat and would cause problems with the sheets, I have now calculated my sail area on that drawing and it is indeed about 200 sq ft. So if I reduced it by 25% maybe it would look more achievable?

I'll re-draw when I have time and show it. David

Thank you all!

Everyone is so welcoming and showing a warm interest in my little boat - really quite exceptional and very encouraging because I am not very mathematical or technical when it comes to the details. Good to meet you Jami and yes, having now had a look at the pictures of the Joe 17 I think we are looking at very similar projects.

I re-read an article by Michael Rogers, who is a JRA member I think, as well as being in the Dinghy Cruising Association. He created a very simple unstayed mast for his dinghy and had two tubes that slot together. Short stubby bit stays fixed to the boat then longer bit slots into it. All very simple if your boat is small and light enough. He wrote that it came from Sunbird Marine. I'm not sure if my boat is small enough to have such a lightweight mast because I have quite a heavy keel. 

Advice on the rig is all very welcome - thank you. I will look at your small scale design, David, when I have a moment - assuming it is on here somewhere. Also helpful to know that the sail I have superimposed would be too big! I had not realised I had increased the sail area so much - I just made it similar, in relation to the boat, to the little drawing in the Junk Rig for Beginners. Anyway I will consider all these suggestions.... My foredeck will need strengthening because already a weakness there. I am certain that it would not be strong enough with nothing underneath a tabernackle anyway. I really can't avoid the buoyancy tank on my boat, but no longer so worried about that so much. I think perhaps being happy with the sail plan and having the mast in exactly the right place is key - I'll keep looking into it. 

Many thanks, again, for all your interest and welcomes.